This invention relates to an ophthalmological apparatus and more particularly to an indirectly illuminating ophthalmological speculum primarily for use in diagnosis and treatments of the surface of the eye.
Ophthalmology is that branch of medicine which involves the eye, its diseases and defects, and its treatment. Many ophthalmological procedures are concerned with the surface of the eye, such as work on the lens, and treatment for cataracts and corneal diseases. Typically, an instrument called an ophthalmoscope is used to assist the ophthalmologist in these procedures.
Although Hermann von Helmholtz, a German physicist and physiologist, is generally credited with inventing the first ophthalmoscope in the early 1850's, there is some evidence that the English mathematician Charles Babbage, was actually the first inventor, some five or ten years earlier. In any event, the modern ophthalmoscope has changed very little from the one envisioned by Babbage or Helmholtz well over 100 years ago. The typical ophthalmoscope includes a tube, a light source such as a light bulb, a mirror at one end of the tube which shines the light through the tube and out the end pointed toward the patient, and a lens which magnifies the view that the ophthalmologist has of the patient's eye. The primary value of the ophthalmoscope is that it permits the ophthalmologist a clear view of the interior and the back surface of the eye. Owing to the lack of a more useful instrument, ophthalmoscopes are typically used for work on the surface of the eye, as well as the interior. While they do provide magnification for the ophthalmologist, and a light source that illuminates the exterior as well as the interior of the eye, these instruments present a number of problems when being used for procedures upon the surface of the eye.
First of all, an ophthalmoscope which is to be used in conjunction with treatment rather than mere examination of the eye, is one which must leave the ophthalmologist's hands free. Such an ophthalmoscope would generally be of the type that is mounted upon the physician's head, rather than the handheld type. In order to provide sufficient illumination from this remote location, the light beam must be narrowly focused and intense. For many procedures the patient remains conscious and finds this intense, narrowly focused light beam extremely uncomfortable. Additionally, there are some indications that the strong narrow light beam may cause damage to the rear of the eye.
Ophthalmoscopes which are worn on the heads of ophthalmologists are also unduly heavy, cumbersome, and uncomfortable to the doctor, because of their self-contained light and power sources.
It can thus be seen that while the traditional ophthalmoscope is useful for procedures involving the interior of the eye, it is ill suited for work upon the surface of the eye.
In addition to the ophthalmoscope a speculum device is often employed to separate the eyelids to provide the ophthalmologist with an unobstructed field to perform procedures such as cataract removal or lens transplants. A typical speculum includes a pair of arms with hooked ends for engaging the eyelids, and a spring for keeping the arms separated.
It is, therefore, an object of this invention to provide a medical instrument for ophthalmological procedures, ideally suited for work on the surface of the eye, which provides illumination that is comfortable for the patient while at the same time maintaining the eyelids separated. It is a further object of this invention to provide an ophthalmological instrument which is safe and avoids the type of damage to the retina, cones, rods, and other parts of the eye that might be caused by intensely focused light. Yet another object of this invention is to provide for the comfort of the ophthalmologist by allowing him or her to wear a lightweight magnifying instrument which need not include a heavy light source. Still another object of this invention is to provide for even, diffuse, substantially tangential illumination of the eye without shadows. A further object of this invention is to provide illumination of the eye without obstruction. These and other objects will in part be apparent and in part pointed out hereinafter.